JP2000150920A - Manufacturing method of Schottky junction type semiconductor diode device. - Google Patents

Abstract

(57) Abstract: A Schottky junction type semiconductor diode device that does not cause a leakage current can be manufactured by a small number of steps in which a lithography method using a photomask is applied only once. . SOLUTION: A semiconductor substrate having an n-type low-resistance semiconductor substrate body for a cathode and an n-type semiconductor layer for a cathode is prepared, a groove is formed in the n-type semiconductor layer for the cathode, and an insulation is provided on an inner surface of the groove. A film is formed, and then a p-type polycrystalline semiconductor layer for a leakage current blocking electrode is buried in a groove of the cathode n-type semiconductor layer via an insulating film, and then a cathode n-type semiconductor layer is formed. A metal electrode for an anode extending between the region defined by the inside of the groove of the layer and the p-type polycrystalline semiconductor layer for the leakage current blocking electrode is defined by the groove of the n-type semiconductor layer for the cathode. It is formed so as to form a Schottky junction with the region that has been formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a Schottky junction type semiconductor diode device.

[0002]

2. Description of the Related Art A method of manufacturing a Schottky junction type semiconductor diode device described below with reference to FIGS. 9 to 13 has been proposed.

That is, for example, a cathode n made of single crystal silicon and having n-type and low resistance
A semiconductor substrate 1 having a low-resistance type semiconductor substrate body 2 and an n-type cathode n-type semiconductor layer 3 made of, for example, single crystal silicon and having an n-type formed on its main surface is prepared (FIG. 9A).

Next, an insulating film 4 made of, for example, silicon oxide is deposited and formed on the cathode n-type semiconductor layer 3 of the semiconductor substrate 1 (FIG. 9B).

Next, a mask layer 5 made of photoresist and having a window 6 for exposing the insulating film 4 to the outside is formed on the insulating film 4 by photolithography (FIG. 9).
C).

Next, a window 7 for exposing the cathode n-type semiconductor layer 3 to the outside is formed in the insulating film 4 by etching the insulating film 4 using the mask layer 5 as a mask (FIG. 10D).

Next, the mask layer 5 is removed from the insulating film 4 forming the window 7 (FIG. 10E).

Next, a groove 8 communicating with the outside is formed in the cathode n-type semiconductor layer 3 by etching using the insulating film 4 forming the window 7 as a mask. Is formed (FIG. 10F).

Next, the insulating film 4 is removed from the cathode n-type semiconductor layer 3 (FIG. 11G).

Next, the grooves 8 of the cathode n-type semiconductor layer 3 are formed by thermal oxidation of the cathode n-type semiconductor layer 3.
An oxide film is formed as an insulating film 9 on the upper surface of the region 3 'defined by the above and on the inner surface of the groove 8 of the n-type semiconductor layer 3 for the cathode (FIG. 11H).

Next, a layer 10 made of, for example, a photoresist is formed on the insulating film 9 by filling the groove 8 of the cathode n-type semiconductor layer 3 with the insulating film 9 interposed therebetween. It is formed to a thickness (FIG. 11I).

Next, a groove 8 of the cathode n-type semiconductor layer 3 is formed by etching the layer 10 from above.
The upper surface is the groove 8 of the insulating n-type semiconductor layer 3 of the insulating film 9.
Buried layer 10 ′ of layer 10 buried via insulating film 9 so as to be on the extension of the upper surface of region 9 ′ on the upper surface of region 3 ′ defined by FIG.
J).

Next, on the region 9 'on the region 3' of the n-type semiconductor layer 3 for the cathode of the insulating film 9 and on the buried layer 10 ', it is made of a photoresist continuously extending therebetween, and A mask layer 11 having a window 12 for exposing a region 9 'of the insulating film 9 on a region 3' of the cathode n-type semiconductor layer 3 to the outside;
Is formed by a photolithography method (FIG. 12).
K).

Next, by etching the insulating film 9 using the mask layer 11 as a mask, the upper surface of the region 3 'defined by the groove 8 of the cathode n-type semiconductor layer 3 is formed on the insulating film 9 to the outside. Is formed (FIG. 12L).

Next, the mask layer 11 is removed from the insulating film 9 and the buried layer 10 ', and the buried layer 10' is removed from the inside of the groove 8 of the cathode n-type semiconductor layer 3 (FIG. 13).
M).

Next, a metal electrode 14 for anode and a leakage current blocking electrode made of, for example, titanium is formed on the insulating film 9 through a window 13 of the insulating film 9 to form a groove 8 of the n-type semiconductor layer 3 for cathode.
Is formed, for example, by a sputtering method so as to form the Schottky junction 15 with the region 3 'formed by the sputtering (FIG. 13N).

The above is the method of manufacturing the conventionally proposed Schottky junction type semiconductor diode device. According to the Schottky junction type semiconductor diode device (FIG. 13N) manufactured by such a conventional method of manufacturing a Schottky junction type semiconductor diode device, the metal electrode 14 for the anode / leakage current blocking electrode is represented by "1" in binary. "(Positive voltage between the positive end and the negative end with reference to the negative end) and" 0 "(zero or negative voltage between the positive end and the negative end with reference to the negative end) The n-type low-resistance semiconductor substrate body 2 for the cathode is connected to the other end of the load having one end connected to the negative end of the signal source. If the signal obtained from the signal source is 2
When the value is "1", a forward voltage is applied to the Schottky junction 15 to turn on the metal electrode 14 for the anode / leakage current blocking electrode and the n-type low-resistance semiconductor substrate body 2 for the cathode. In this case, the metal electrode 14 for the anode and the leakage current blocking electrode is
A region opposed to the side surface of the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 via the insulating film 9, but defined by the groove 8 of the cathode n-type semiconductor layer 3. In 3 ', a depletion layer is hardly formed from the region of the insulating film 9 on the side surface of the region 3' defined by the trench 8 of the n-type semiconductor layer 3 for the cathode. In the case where a signal obtained from a signal source takes "0" in binary display, zero or reverse voltage is applied to the Schottky junction 15, Between the anode / leakage current blocking electrode metal electrode 14 and the cathode n-type low resistance semiconductor substrate body 2 is turned off, and in this case, the anode / leakage current blocking electrode metal electrode 14 is Through the cathode n-type semiconductor layer 3 Since it faces the side surface of the region 3 ′ defined by the groove 8, a depletion layer is formed in the region 3 ′ of the insulating film 9 in the cathode 3 of the n-type semiconductor layer 3. From the region on the side surface of the region 3 'defined by the groove 8 of the n-type semiconductor layer 3 so as to completely fill the entire region 3', so that a leakage current flows to the load. A function that a state in which no current is supplied can be obtained without any problem.

As described above, according to the conventional method for manufacturing a Schottky junction type semiconductor diode device shown in FIGS. 9 to 13, a Schottky junction type semiconductor diode device having the above-described functions can be manufactured.

[0019]

The conventional method of manufacturing the Schottky junction type semiconductor diode device shown in FIGS.
N-type low-resistance semiconductor substrate body 2 for cathode and n for cathode
A semiconductor substrate 1 having a mold semiconductor layer 3 is prepared (FIG. 9).
A), a groove 8 is formed in the cathode n-type semiconductor layer 3 (FIG. 10F), and the upper surface of the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 and the cathode n-type An insulating film 9 is formed on the inner surface of the groove 8 of the semiconductor layer 3 (FIG. 11H), and then the groove 8 of the cathode n-type semiconductor layer 3 is filled with a buried layer 10 'via the insulating film 9 (see FIG. 11H). 12
J) Next, a photoresist is formed on the region 9 ′ of the insulating film 9 on the upper surface of the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 and on the buried layer 10 ′. And a mask layer 11 having a window 12 for exposing a region 9 'of the insulating film 9 to the outside is formed by photolithography (FIG. 12K). Then, using the mask layer 11 as a mask, the insulating film is formed. 9, a window 13 is formed to expose the upper surface of the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 to the outside (FIG. 12L). A metal electrode for a leakage current blocking electrode is formed so as to form a Schottky junction with the region defined by the groove in the n-type semiconductor layer for the cathode through the window of the insulating film. (FIG. 13N).

In this case, the photo-resist is formed on the insulating film 9 on the region 9 'on the upper surface of the region 3' defined by the groove 8 of the cathode n-type semiconductor layer 3 and on the buried layer 10 '. A photomask is used to form a mask layer 11 made of resist and having a window 12 that exposes the region 9 ′ of the insulating film 9 to the outside by a photolithography method.
A margin is required for the alignment of the photomask.

Accordingly, when the groove 8 is formed in the n-type semiconductor layer 3 for the cathode, thereby forming the region 3 ′ defined by the groove 8 in the n-type semiconductor layer 3 for the cathode, The area 3 ′ is forced to become larger in the cross section at least by the margin required for the alignment of the photomask described above.

For this reason, the Schottky junction type semiconductor diode device manufactured by the method of manufacturing the conventional Schottky junction type semiconductor diode device shown in FIGS.
4 is connected to the positive terminal of the signal source, and the n-type low-resistance semiconductor substrate body 2 for the cathode is used by connecting one terminal to the other terminal of the load connected to the negative terminal of the signal source. Takes a binary value of “0”, thereby forming a depletion layer in the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3, Depending on the voltage value of the signal from the signal source, there is a high possibility that the depletion layer may not reach a state in which the depletion layer is formed so as to completely fill the entire region 3 ′. It has a high possibility of flowing, and thus has a drawback that a large amount of power is consumed when a state where no current is supplied to the load is obtained.

In the case of the conventional method of manufacturing the Schottky junction type semiconductor diode device shown in FIGS. 9 to 13, the semiconductor substrate 1 having the n-type low resistance semiconductor substrate body 2 for the cathode and the n-type semiconductor layer 3 for the cathode is used. 9A, and an insulating film 4 is formed on the cathode n-type semiconductor layer 3 (FIG. 9A).
B) On the insulating film 4, a mask layer 5 having a window 6 for exposing it to the outside is formed by photolithography (FIG. 9C), and the window 7 is formed on the insulating film 4 using the mask layer 5.
(FIG. 10D), a groove 8 is formed in the cathode n-type semiconductor layer 3 using the insulating film 4 having the window 7 as a mask (FIG. 10F), and the groove of the cathode n-type semiconductor layer 3 is formed. An insulating film 9 is formed on the upper surface of the region 3 ′ defined by 8 and on the inner surface of the groove 8 of the cathode n-type semiconductor layer 3 (FIG. 11H). The trench 8 is filled with a buried layer 10 'via an insulating film 9 (FIG. 1).
2J) Then, the cathode n-type semiconductor layer 3 of the insulating film 9
A window 12 made of photoresist and exposing the region 9 'of the insulating film 9 to the outside is formed on the region 9' on the upper surface of the region 3 'defined by the groove 8 and the buried layer 10'. A mask layer 11 was formed by photolithography (FIG. 12K), and was then defined in the insulating film 9 by the grooves 8 of the cathode n-type semiconductor layer 3 using the mask layer 11 as a mask. A window 13 is formed so that the upper surface of the region 3 ′ faces the outside (FIG. 12L). Next, a metal electrode 14 for an anode and a leakage current blocking electrode is formed on the insulating film 9 through a window 13 of the insulating film 9. A Schottky junction 15 is formed between the n-type semiconductor layer 3 and the region 3 'defined by the groove 8 (FIG. 13N).

Therefore, the mask layer 5 is formed on the insulating film 4 by the photolithography method (FIG. 9C), and the region 3 of the insulating film 9 defined by the groove 8 of the cathode n-type semiconductor layer 3 is formed. The process using a photomask to which a photolithography method is applied is also performed twice, that is, when a mask layer 11 is formed by a photolithography method on a region 9 ′ on the upper surface of the ′ ′ and on a buried layer 10 ′. ing.

For this reason, manufacturing a Schottky junction type semiconductor diode device requires a large number of steps and has the disadvantage that two photomasks must be prepared.

Accordingly, the present invention proposes a novel method for manufacturing a Schottky junction type semiconductor diode device which does not have the above-mentioned disadvantages.

[0027]

A method of manufacturing a Schottky junction type semiconductor diode device according to the first invention of the present application is as follows.
(1) a step of preparing a semiconductor substrate having a cathode n-type low-resistance semiconductor substrate main body and a cathode n-type semiconductor layer formed on a main surface thereof; and (2) a step of preparing a semiconductor substrate having the cathode n-type semiconductor layer. Forming a first insulating film; and (3) depositing and forming a second insulating film having oxidation resistance and a third insulating film on the first insulating film in that order. Forming an insulating film stack of the first, second, and third insulating films, and (4) etching the insulating film stack using a mask layer to form the insulating film stack. Forming a window for exposing the cathode n-type semiconductor layer to the outside, and (5) forming the window in the insulating film laminate, and then stacking the insulating film on the cathode n-type semiconductor layer. Etching process using the body as a mask Forming a groove in the cathode n-type semiconductor layer, and (6) forming the groove in the cathode n-type semiconductor layer; Removing the third insulating film in the second and first insulating films from above the second insulating film; and (7) removing the third insulating film from above the second insulating film. After the step, the n-type semiconductor layer for the cathode is subjected to a thermal oxidation treatment using the second insulating film as a mask, so that
Forming an oxide film as a fourth insulating film; (8)
The fourth surface is formed on the inner surface of the groove of the n-type semiconductor layer for a cathode.
Forming a p-type polycrystalline semiconductor layer for a leakage current blocking electrode via the fourth insulating film in the groove of the n-type semiconductor layer for the cathode after the step of forming the insulating film of (9) After the step of burying the p-type polycrystalline semiconductor layer for the leakage current blocking electrode in the groove of the n-type cathode semiconductor layer, the second and first insulating films are replaced with the n-type cathode layer. Removing the second and first insulating films from the n-type semiconductor layer for the cathode, and removing the second and first insulating films from the n-type semiconductor layer for the cathode, and then removing the n-type semiconductor layer for the cathode and the leakage current blocking electrode. Forming an anode metal electrode extending continuously between the p-type polycrystalline semiconductor layers so as to form a Schottky junction with the cathode n-type semiconductor layer.

The method of manufacturing a Schottky junction type semiconductor diode device according to the second invention of the present application includes (1) the steps (1) to (7) in the above-described method of manufacturing a Schottky junction type semiconductor diode device of the first invention of the present application. When,
(2) After the step of forming the fourth insulating film on the inner surface of the groove of the cathode n-type semiconductor layer, the second and first insulating films are removed from the cathode n-type semiconductor layer. After the step and (3) the step of removing the second and first insulating films from the n-type semiconductor layer for the cathode, the step of removing the n-type semiconductor layer for the cathode and the fourth insulating film between the n-type semiconductor layer and the fourth insulating film Forming a continuously extended metal electrode for anode and leakage current blocking electrode so as to form a Schottky junction with the n-type semiconductor layer for cathode.

[0029]

Embodiment 1 Next, a first embodiment of a method for manufacturing a Schottky junction type semiconductor diode device according to the present invention will be described with reference to FIGS. 1 to 5, parts corresponding to those in FIGS. 9 to 13 are denoted by the same reference numerals.

The method of manufacturing the Schottky junction semiconductor diode device according to the present invention shown in FIGS. 1 to 5 takes the following sequential steps to manufacture a target Schottky junction semiconductor diode device.

That is, as in the case of the conventional Schottky junction type semiconductor diode device shown in FIGS. 9 to 13, the same n-type low-resistance cathode is made of, for example, single-crystal silicon and has n-type and low resistance. A semiconductor substrate main body 2 and an n-type cathode n-type semiconductor layer 3 made of, for example, single crystal silicon and having an n-type formed on the main surface thereof
Is prepared (FIG. 1A).

Next, a first insulating film 21 made of, for example, silicon oxide is formed on the cathode n-type semiconductor layer 3 of the semiconductor substrate 1 (FIG. 1B).

Next, on the first insulating film 21, a second insulating film 22 made of, for example, silicon nitride having oxidation resistance is formed.
And a third insulating film 23 made of, for example, silicon oxide, are deposited and formed in that order to form an insulating film laminate 20 including the first, second, and third insulating films 21, 22, and 23. (FIG. 1C).

Next, a window 6 made of photoresist and made to expose the insulating film laminate 20 to the outside is formed on the insulating film laminate 20.
Is formed by a photolithography method (FIG. 2D).

Next, the insulating film laminate 2 is etched by using the mask layer 5 on the insulating film laminate 20.
0, window 2 for exposing cathode n-type semiconductor layer 3 to the outside
6 (FIG. 2E).

Next, the mask layer 5 is removed from the insulating film stack 20 forming the window 26 (FIG. 2F).

Next, a groove 8 is formed in the cathode n-type semiconductor layer 3 by etching the cathode n-type semiconductor layer 3 using the insulating film laminate 20 forming the window 26 as a mask. (FIG. 3G).

Next, the third insulating film 23 which is the uppermost layer of the third, second and first insulating films 23, 22 and 21 constituting the insulating film laminate 20 is replaced with the second insulating film. It is removed from the film 22 (FIG. 3H).

Next, an oxide film is formed on the inner surface of the groove 8 of the cathode n-type semiconductor layer 3 by a thermal oxidation process on the cathode n-type semiconductor layer 3 using the second insulating film 22 as a mask. It is formed as an insulating film 24 (FIG. 3I).

Next, on the insulating film laminate of the fourth insulating film 24 and the first and second insulating films 21 and 22, a multi-layered structure in which boron, for example, which is continuously extended therebetween, is introduced. A p-type polycrystalline semiconductor layer 27 made of a crystalline semiconductor layer is formed so as to completely fill the groove 8 of the cathode n-type semiconductor layer 3 with the fourth insulating film 24 interposed therebetween and to have a flat upper surface. (FIG. 4J).

Next, for the p-type polycrystalline semiconductor layer 27,
By etching from above, the p-type polycrystalline semiconductor layer 27 for the leakage current blocking electrode is filled from the p-type polycrystalline semiconductor layer 27 with the trench 8 of the n-type semiconductor layer 3 for the cathode via the fourth insulating film 24. A semiconductor layer 27 'is formed (FIG. 4K).

Next, the second and first insulating films 22 and 21
Is removed from the region 3 'defined by the groove 8 of the n-type semiconductor layer 3 for the cathode (FIG. 5L).

Next, the region 3 'defined by the groove 8 of the n-type semiconductor layer 3 for the cathode and the p
An anode metal electrode 28 extending continuously between them is Schottky-bonded to the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 on the polycrystalline semiconductor layer 27 ′. 15 (see FIG. 5).
M).

The above is the first embodiment of the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention.

According to the Schottky junction type semiconductor diode device (FIG. 5M) manufactured by the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention,
According to the Schottky junction type semiconductor diode device manufactured by the conventional method of manufacturing a Schottky junction type semiconductor diode device shown in FIGS. 9 to 13, the anode metal electrode 28 is set to “1” (positive polarity) in binary display. A signal that takes a positive voltage between the negative terminal and the negative terminal with respect to the negative terminal, and a signal that takes “0” (zero or negative voltage with the negative terminal between the positive terminal and the negative terminal as the reference). If the signal source is connected to the positive terminal of the obtained signal source and the n-type low-resistance semiconductor substrate body for cathode 2 is used by connecting one end to the other end of the load connected to the negative terminal of the signal source, Is "1" in binary notation, a forward voltage is applied to the Schottky junction 15 so that the anode metal electrode 28 and the cathode n-type low-resistance semiconductor substrate main body 2 are turned on. And this place In the state where the p-type polycrystalline semiconductor layer 27 'for the leakage current blocking electrode is supplied with the potential applied to the metal electrode 28 for the anode, the n-type semiconductor layer for the cathode is interposed via the fourth insulating film. 3 is opposed to the side surface of the region 3 ′ defined by the groove 8,
In the region 3 ′ defined by the groove 8 of the mold semiconductor layer 3,
The depletion layer hardly extends from the region of the fourth insulating film 24 on the side surface of the region 3 ′ defined by the groove 8 of the n-type semiconductor layer 3 for the cathode, so that the load is not affected by the load.
It is possible to obtain a state where current is supplied,
When the signal obtained from the signal source takes "0" in binary display, a zero or reverse voltage is applied to the Schottky junction 15, so that the anode metal electrode 28 and the cathode n-type low-resistance semiconductor substrate main body 2 Goes off, and
In this case, the p-type polycrystalline semiconductor layer 2 for the leakage current blocking electrode
7 ′, the groove 8 of the cathode n-type semiconductor layer 3 through the fourth insulating film 24 in a state where the potential given in this case is applied through the anode metal electrode 28. In the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3, a depletion layer is formed in the region 3 ′ of the cathode n-type semiconductor layer 3. It is formed so as to extend from the area on the side of the area 3 'defined by the groove 8 so as to completely fill the entire area of the area 3', so that current is supplied to the load without leak current. You can get a state that has not been let,
Function.

As described above, according to the method of manufacturing the Schottky junction semiconductor diode device of the present invention shown in FIGS. 1 to 5, it is possible to manufacture the Schottky junction semiconductor diode device having the above-described functions and effects. .

The method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. 1 to 5 includes a method of manufacturing a semiconductor substrate 1 having an n-type low resistance semiconductor substrate body 2 for a cathode and an n-type semiconductor layer 3 for a cathode. Prepared (FIG. 1A), an insulating film stack 20 of the first, second and third insulating films 21, 22 and 23 forming windows 26 is used as a mask in the cathode n-type semiconductor layer 3. A groove 8 is formed by etching (FIG. 3G), a fourth insulating film 24 is formed on the inner surface of the groove 8 (FIG. 3I), and then a groove 8 in the n-type semiconductor layer 3 for a cathode is formed. The p-type polycrystalline semiconductor layer 27 'for a leakage current blocking electrode is
A buried layer is formed (FIG. 4K). Next, the region 3 'is defined on the region 3' defined by the inside of the groove 8 of the cathode n-type semiconductor layer 3 and on the p-type polycrystalline semiconductor layer 27 'for the leakage current blocking electrode. The anode metal electrode 28 extending between the region 3 'and the leakage current blocking electrode p-type polycrystalline semiconductor layer 27' in a state where nothing is formed on the n-type semiconductor layer 3 ' A Schottky junction 15 is formed with the region 3 'defined by the groove 8 (FIG. 5M).

Therefore, unlike the method of manufacturing the conventional Schottky junction type semiconductor diode device shown in FIGS. 9 to 13, it is not necessary to provide a margin for positioning the photomask. N-type semiconductor layer 3 for
When a region 8 is formed in the n-type semiconductor layer 3 for the cathode, thereby forming a region 3 'defined by the groove 8, the conventional Schottky junction type semiconductor diode device shown in FIGS. As in the case of the manufacturing method, the region 3 '
However, when viewed from the cross-section, it is not necessary to increase the size of the photomask by at least the margin required for positioning the photomask.

Therefore, the Schottky junction type semiconductor diode device manufactured by the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. 1 to 5 is connected to the anode metal electrode 28 as described above. N-type low-resistance semiconductor substrate body 2 for cathode connected to the active end
When one end is connected to the other end of the load having one end connected to the negative end of the signal source, the signal obtained from the signal source takes a binary "0", so that the cathode n
When the depletion layer is formed to extend in the region 3 ′ defined by the trench 8 of the type semiconductor layer 3, the depletion layer is formed over the entire region 3 ′ depending on the voltage value of the signal from the signal source. In the case of the Schottky junction type semiconductor diode device manufactured by the conventional method of manufacturing a Schottky junction type semiconductor diode device shown in FIGS. Therefore, it has only a low possibility that a leakage current flows, and therefore, when a state where no current is supplied to the load is obtained, a large power consumption is substantially accompanied. You can prevent it from being done.

In the case of the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. 1 to 5, a semiconductor substrate 1 having a cathode n-type low-resistance semiconductor substrate body 2 and a cathode n-type semiconductor layer 3 is provided. Prepared (FIG. 1A),
On the n-type semiconductor layer 3 for the cathode, an insulating film laminate 20 including first, second, and third insulating films 21, 22, and 23.
Is formed (FIG. 1C), and a mask layer 5 having a window 6 for exposing it to the outside is formed on the insulating film laminate 20 by photolithography (FIG. 2D), and the mask layer 5 is formed.
A window 26 is formed in the insulating film laminate 20 by using
E), using the insulating film laminate 20 having the window 26 as a mask, forming a groove 8 in the cathode n-type semiconductor layer 3 (FIG. 3G), and forming an inner surface of the groove 8 in the cathode n-type semiconductor layer 3. An insulating film 24 is formed thereon (FIG. 3I), and a p-type polycrystalline semiconductor layer 27 'for a leakage current blocking electrode is buried in the groove 8 of the n-type semiconductor layer 3 for the cathode via the insulating film 24. Formed (FIG. 4J), and then the trench 8 of the n-type semiconductor layer 3 for cathode is formed.
The metal electrode 28 for the anode is defined by the groove 8 of the n-type semiconductor layer 3 for the cathode on the region 3 'defined by the above and on the p-type polycrystalline semiconductor layer 27' for the leakage current blocking electrode. A Schottky junction 15 is formed with the region 3 '(FIG. 5M).

Therefore, the mask layer 5 is formed on the insulating film laminate 20.
Is formed only once by a photolithography method (FIG. 2D), a process using a photolithography method using a photomask is performed.

For this reason, only one photomask is required to manufacture a Schottky junction type semiconductor diode device, and the method of manufacturing the conventional Schottky junction type semiconductor diode device shown in FIGS. As compared with the case, a Schottky junction type semiconductor diode device can be manufactured with a smaller number of steps.

In the step of forming the fourth insulating film 24 on the inner surface of the groove 8 of the cathode n-type semiconductor layer 3 (FIG. 3I), the second insulating film 22 having oxidation resistance is used as a mask. However, since the second insulating film 22 is formed on the cathode n-type semiconductor layer 3 via the first insulating film 21, the second insulating film 22 is formed on the cathode n-type semiconductor layer 3. It can be formed well on the layer.

[0054]

Embodiment 2 Next, a second embodiment of a method for manufacturing a Schottky junction type semiconductor diode device according to the present invention will be described with reference to FIG. In FIG. 6, FIGS.
9 and 13 are denoted by the same reference numerals.

In the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIG. 6, a target Schottky junction type semiconductor diode device is manufactured through the following sequential steps.

That is, in the manufacturing method of the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. 1 to 5, the sequential steps shown in FIGS. 1A to 1C, FIGS. As shown in FIG. 5, the groove 8 of the cathode n-type semiconductor layer 3 of the semiconductor substrate 1 having the cathode n-type low resistance semiconductor substrate body 2 and the cathode n-type semiconductor layer 3
The first insulating film 21 made of, for example, silicon oxide and the second insulating film 22 having oxidation resistance are left on the region 3 'defined by After obtaining a configuration in which a fourth insulating film 24 made of an oxide film is formed on the inner surface of the groove 8 of the n-type semiconductor layer 3 for use,
Then, the insulating film stack of the second insulating films 22 and 21 is removed from the region 3 'defined by the groove 8 of the cathode n-type semiconductor layer 3 (FIG. 6B).

In this case, the fourth insulating film 24 made of an oxide film
When the n-type semiconductor layer 3 for cathode is made of silicon,
Since the first insulating film 22 is made of silicon oxide, the first and fourth insulating films 21 and 2 are made of silicon oxide.
4 is made of the same silicon oxide, and therefore, if the first insulating film 21 is to be removed from the region 3 'of the cathode n-type semiconductor layer 3 by using an etchant capable of removing and removing the same, There is a concern that the fourth insulating film 24 is also removed by leaching. In this case, if the fourth insulating film 24 is formed sufficiently thicker than the first insulating film 21, the fourth insulating film 24 is removed.
There is no concern if the thickness is smaller than the original thickness.

Next, on the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 and on the fourth insulating film 2
A metal electrode 14 for anode and leakage current blocking electrode is continuously extended between them, and a Schottky junction 15 is formed between the metal electrode 14 for anode and leakage current blocking electrode and the region 3 ′ defined by the groove 8 of the n-type semiconductor layer 3 for cathode. (FIG. 6C).

The above is the second embodiment of the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention.

According to the Schottky junction type semiconductor diode device manufactured by the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention (FIG. 6C),
According to the Schottky junction type semiconductor diode device manufactured by the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. 1 to 5, the metal electrode 14 for the anode and the leakage current blocking electrode is connected to the positive electrode of the signal source. Connected to the active end, and the n-type low-resistance semiconductor substrate body 2 for the cathode is
If one end is connected to the other end of the load connected to the negative end of the signal source and the signal obtained from the signal source takes "1" in binary display, the forward voltage is applied to the Schottky junction 15. By being applied, the metal electrode 14 for the anode and leakage current blocking electrode and the n-type low-resistance semiconductor substrate body 2 for the cathode are turned on, and in this case, the metal electrode for the anode and leakage current blocking electrode 14 is opposed to the side surface of the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 via the fourth insulating film. Defined area 3 '
In the depletion layer, the depletion layer hardly extends from the region on the side surface of the region 3 ′ of the fourth insulating film 24, which is defined by the groove 8 of the n-type semiconductor layer 3 for cathode. It is possible to obtain a state in which a current is supplied to the load, and when the signal obtained from the signal source takes “0” in binary display, zero or reverse voltage is applied to the Schottky junction 15. The metal electrode 14 for the anode and leakage current blocking electrode and the n-type low-resistance semiconductor substrate body 2 for the cathode are turned off, and in this case, the metal electrode 14 for the anode and leakage current blocking electrode becomes the fourth electrode. Is opposed to the side surface of the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 via the insulating film 24 of
In the region 3 ′ defined by the groove 8 of the mold semiconductor layer 3,
The depletion layer is formed so as to extend from the region on the side surface of the region 3 ′ defined by the groove 8 of the cathode n-type semiconductor layer 3 so as to completely fill the entire region 3 ′.
A function is provided in which a state in which no current is supplied can be obtained without causing a leakage current to flow through the load.

As described above, according to the method of manufacturing a Schottky junction semiconductor diode device according to the present invention shown in FIG. 6, a Schottky junction semiconductor diode device having the above-described functions and effects can be manufactured.

In the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIG. 6, a semiconductor substrate 1 having an n-type low resistance semiconductor substrate body 2 for a cathode and an n-type semiconductor layer 3 for a cathode is prepared. 1A), the cathode n-type semiconductor layer 3 is subjected to an etching process using the insulating film stack 20 including the first, second and third insulating films 21, 22 and 23 forming the window 26 as a mask. ,
A groove 8 is formed (FIG. 3G), a fourth insulating film 24 is formed on the inner surface of the groove 8 (FIG. 3I), and then defined by the inside of the groove 8 of the cathode n-type semiconductor layer 3. On the region 3 ′ and the fourth insulating film 24, in a state where nothing is formed on the region 3 ′, the region 3 ′ and the region 3 ′ defined by the groove 8 of the n-type semiconductor layer 3 for cathode are formed. Metal electrode 1 for anode and leakage current blocking electrode extending between insulating films 24
4 are formed so as to form a Schottky junction 15 with the region 3 'defined by the groove 8 of the cathode n-type semiconductor layer 3 (FIG. 5M).

Therefore, similarly to the case of the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. 1 to 5, the method of manufacturing the conventional Schottky junction type semiconductor diode device shown in FIGS. As described above, it is not necessary to provide a margin for the alignment of the photomask, and therefore, the groove 8 is formed in the n-type semiconductor layer 3 for the cathode, thereby forming the groove 8 in the n-type semiconductor layer 3 for the cathode. When forming a region 3 'defined by
As in the case of the conventional method of manufacturing a Schottky junction type semiconductor diode device shown in FIG. 13, the region 3 'becomes larger at least by a margin necessary for the alignment of the photomask described above in a cross section. There is no need to be forced.

Therefore, a Schottky junction type semiconductor diode device manufactured by the method of manufacturing a Schottky junction type semiconductor diode device according to the present invention shown in FIG.
According to the Schottky junction type semiconductor diode device manufactured by the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIG. 5, the metal electrode 14 for anode and leakage current blocking electrode is connected to the positive terminal of the signal source. When the n-type low-resistance semiconductor substrate body 2 for the cathode is used by connecting one end to the other end of the load connected to the negative end of the signal source, the signal obtained from the signal source is represented by a binary " By taking “0”, when the depletion layer is formed to extend in the region 3 ′ defined by the groove 8 of the n-type semiconductor layer 3 for cathode, the depletion layer forms the signal of the signal from the signal source. Depending on the voltage value, there is a possibility that the state in which the region is not formed so as to completely fill the entire region 3 ′ may not be reached. The conventional Schottky junction type semiconductor diode shown in FIGS. A state in which the current is not supplied to the load because the Schottky junction type semiconductor diode device manufactured by the manufacturing method of the device has only a low level, and thus has a low risk of leakage current. , It is possible to substantially avoid large power consumption.

In the case of the method for manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIG. 6, FIGS.
A semiconductor substrate 1 having a cathode n-type low-resistance semiconductor substrate main body 2 and a cathode n-type semiconductor layer 3 is prepared according to the method of manufacturing a Schottky junction type semiconductor diode device according to the present invention shown in FIG. , First, second and third insulating films 21 and 22 on the cathode n-type semiconductor layer 3.
And 23 are formed (FIG. 1C).
A window 6 on the insulating film laminate 20 to expose it to the outside.
Is formed by photolithography (FIG. 2D), a window 26 is formed in the insulating film stack 20 using the mask layer 5 (FIG. 2E), and the insulating film stack 20 having the window 26 is formed. Is used as a mask, and n
A groove 8 is formed in the semiconductor layer 3 (FIG. 3G), and a fourth insulating film 24 is formed on the inner surface of the groove 8 of the n-type semiconductor layer 3 for the cathode (FIG. 3I). On the region 3 ′ defined by the groove 8 of the type semiconductor layer 3 and on the fourth insulating film 24, the metal electrode 14 for both the anode and the leakage current blocking electrode is provided with the groove 8 of the n-type semiconductor layer 3 for the cathode. A Schottky junction 15 is formed with the region 3 'defined by the above (FIG. 5M).

Accordingly, the mask layer 5 is formed by photolithography on the insulating film stack 20 in the same manner as in the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. 1 to 5 (FIG. 2D). Only once in the case, a process using a photolithography method using a photomask is performed.

Therefore, as in the case of the method of manufacturing the Schottky junction semiconductor diode device according to the present invention shown in FIGS. 1 to 5, only one photomask is prepared for manufacturing the Schottky junction semiconductor diode device. It is not necessary, and the Schottky junction type semiconductor diode device can be manufactured with a smaller number of steps as compared with the conventional method of manufacturing a Schottky junction type semiconductor diode device shown in FIGS.

In the above description, only the two embodiments of the method of manufacturing the Schottky junction type semiconductor diode device according to the present invention are described. For example, the Schottky junction type semiconductor diode device according to the present invention shown in FIGS. After the sequential steps up to the step shown in FIG. 5M in the manufacturing method, a metal electrode 29 made of, for example, aluminum is formed on the anode metal electrode 28 as shown in FIG. It is also possible to manufacture a Schottky junction type semiconductor diode device having a configuration in which it can be connected to the outside, for example, by connecting to one end of a signal source via the metal electrode 29 as described above. After the sequential steps up to the step shown in FIG. 6C in the method of manufacturing a Schottky junction type semiconductor diode device according to
As shown in FIG. 8, a metal electrode 30 made of, for example, aluminum is formed on the metal electrode 14 for the anode and the leakage current blocking electrode.
And the trench 8 of the cathode n-type semiconductor layer 3 is connected to the fourth insulating film 2.
4 and a metal electrode 14 for anode / leakage current blocking electrode, which is formed to have a large thickness so as to be buried via the metal electrode 14 for anode / leakage current blocking electrode and to have a flat upper surface.
Can be manufactured via a metal electrode 30 to connect to one end of a signal source as described above, such as a Schottky junction type semiconductor diode device. Various modifications and changes may be made without departing from the scope of the present invention.

[0069]

According to the present invention, a Schottky junction type semiconductor diode device having no possibility of generating a leakage current can be manufactured by a small number of steps in which a lithography method using a photomask is applied only once.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing sequential steps in a first embodiment of a method for manufacturing a Schottky junction semiconductor diode device according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a first embodiment of a method of manufacturing a Schottky junction type semiconductor diode device according to the present invention, which is a sequential step following the sequential step of FIG.

FIG. 3 is a schematic cross-sectional view showing a first embodiment of a method for manufacturing a Schottky junction type semiconductor diode device according to the present invention, which is a sequential step following the sequential step of FIG.

FIG. 4 is a schematic cross-sectional view showing a first embodiment of a method for manufacturing a Schottky junction type semiconductor diode device according to the present invention, which is a sequential step following the sequential step of FIG.

FIG. 5 is a schematic cross-sectional view showing a first embodiment of a method for manufacturing a Schottky junction type semiconductor diode device according to the present invention, which is a sequential step following the sequential step of FIG.

FIG. 6 is a schematic sectional view showing sequential steps in a second embodiment of a method for manufacturing a Schottky junction type semiconductor diode device according to the present invention.

FIG. 7 is a schematic sectional view showing another embodiment of the method for manufacturing the Schottky junction type semiconductor diode device according to the present invention.

FIG. 8 is a schematic sectional view showing still another embodiment of the method for manufacturing the Schottky junction type semiconductor diode device according to the present invention.

FIG. 9 is a schematic cross-sectional view showing a method of manufacturing a conventional Schottky junction type semiconductor diode device in sequential steps.

FIG. 10 is a schematic cross-sectional view showing a manufacturing method of a conventional Schottky junction type semiconductor diode device, which is a sequential step following the sequential step of FIG.

FIG. 11 is a schematic cross-sectional view showing a manufacturing method of a conventional Schottky junction type semiconductor diode device, which is a sequential step following the sequential step of FIG.

FIG. 12 is a schematic cross-sectional view showing a manufacturing method of a conventional Schottky junction type semiconductor diode device, which is a sequential step following the sequential step of FIG. 11;

FIG. 13 is a schematic cross-sectional view showing a manufacturing method of the conventional Schottky junction type semiconductor diode device, which is a sequential step following the sequential step of FIG.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 semiconductor substrate 2 n-type low-resistance semiconductor substrate main body for cathode 3 n-type semiconductor layer for cathode 4 insulating film 5 mask layer 6, 7 window 8 groove of n-type semiconductor layer 3 for cathode 9 insulating film 10 'buried layer 11 mask Layer 12, 13 Window 14 Metal electrode for anode and leakage current blocking electrode 15 Schottky junction 20 Insulating film laminate 21, 22, 23 Insulating film 27 P-type polycrystalline semiconductor layer 27 'P-type polycrystalline semiconductor for leakage current blocking electrode Layer 28 Metal electrode for anode 29, 30 Metal electrode

Claims (2)

[Claims] A step of preparing a semiconductor substrate having a cathode n-type low-resistance semiconductor substrate main body and a cathode n-type semiconductor layer formed on a main surface thereof; Forming a first insulating film; and depositing and forming an oxidation-resistant second insulating film and a third insulating film on the first insulating film in this order. A step of forming an insulating film stack of first, second and third insulating films; and an etching process using a mask layer on the insulating film stack to form the n-type semiconductor for a cathode on the insulating film stack. A step of forming a window that exposes the layer to the outside, and after the step of forming the window in the insulating film stack, an etching process using the insulating film stack as a mask on the cathode n-type semiconductor layer, Above cathode Forming a groove in the n-type semiconductor layer for use, and forming the groove in the n-type semiconductor layer for the cathode, and then forming the third, second, and first parts constituting the insulating film laminate. After removing the third insulating film in the insulating film from the second insulating film, and removing the third insulating film from the second insulating film, the n-type cathode is removed. The above-mentioned second for the semiconductor layer
Forming an oxide film as a fourth insulating film on the inner surface of the groove of the cathode n-type semiconductor layer by thermal oxidation using the insulating film as a mask; The fourth surface is provided on the inner surface of the groove.
Forming a p-type polycrystalline semiconductor layer for a leakage current blocking electrode via the fourth insulating film in the groove of the n-type semiconductor layer for the cathode after the step of forming the insulating film of After the step of burying the p-type polycrystalline semiconductor layer for a leakage current blocking electrode in the groove of the n-type semiconductor layer for the cathode, the second and first insulating films are replaced with the n-type semiconductor layer for the cathode. After removing from above and removing the second and first insulating films from above the n-type semiconductor layer for cathode, the n-type semiconductor layer for cathode and the p-type polycrystalline semiconductor for leakage current blocking electrode On the layer,
Forming a metal electrode for an anode continuously extending between them so as to form a Schottky junction with the n-type semiconductor layer for a cathode. Manufacturing method. A step of preparing a semiconductor substrate having a cathode n-type low-resistance semiconductor substrate main body and a cathode n-type semiconductor layer formed on a main surface thereof; Forming a first insulating film; and depositing and forming an oxidation-resistant second insulating film and a third insulating film on the first insulating film in this order. A step of forming an insulating film stack of first, second and third insulating films; and an etching process using a mask layer on the insulating film stack to form the n-type semiconductor for a cathode on the insulating film stack. A step of forming a window that exposes the layer to the outside, and after the step of forming the window in the insulating film stack, an etching process using the insulating film stack as a mask on the cathode n-type semiconductor layer, Above cathode Forming a groove in the n-type semiconductor layer for use, and forming the groove in the n-type semiconductor layer for the cathode, and then forming the third, second, and first parts constituting the insulating film laminate. After removing the third insulating film in the insulating film from the second insulating film, and removing the third insulating film from the second insulating film, the n-type cathode is removed. The above-mentioned second for the semiconductor layer
Forming an oxide film as a fourth insulating film on the inner surface of the groove of the cathode n-type semiconductor layer by thermal oxidation using the insulating film as a mask; The fourth surface is provided on the inner surface of the groove.
Removing the second and first insulating films from above the cathode n-type semiconductor layer after the step of forming the insulating film, and removing the second and first insulating films from the cathode n-type semiconductor layer. After the step of removing from the layer, on the cathode n-type semiconductor layer and the fourth insulating film, the anode / leakage current blocking electrode metal electrode continuously extending therebetween is placed on the cathode n-type semiconductor layer. Forming a Schottky junction with the semiconductor layer.